For growers who have yet to side dress their corn this year, adding AMS to the urea application is a good bet. Rod Gustafson, Federated agronomist at the Albertville location, noted that sulfur (S), like nitrogen, leaches from the soil, so any S in the starter fertilizer is generally gone by this point in the season.

The highly soluble AMS blends well with urea, making it cost- and time-effective to side dress these nutrients in one application. Sulfur is important for key plant functions, but plants can only take up S in the sulfate form, which AMS provides.

Blending AMS with the urea at a rate of 25 lb./ac. of sulfur (100 lbs. or more of 21-0-0-24S ammonium sulfate) will give corn the S boost it needs – “especially on the coarser textured and sandy soils in our area,” he said. The ideal time to side dress this blend is at the V5 to V6 stage.

Growers who rotate from corn to soybeans may or may not find that last year’s corn crop left behind enough sulfur for this year’s soybeans, but if not, side dressing AMS is recommended at 10-25 lbs./ac. of sulfur (which equates to 40-100 lbs. of 21-0-0-24S AMS), according to Gustafson. (However, he added that Gypsoil – a combination of sulfur and calcium – may be the best recommendation for soybeans. See Gypsoil fact sheet .)

If the previous crop ahead this year’s soybeans was not fertilized with sulfur, it would be a very good recommendation to fertilize this year’s soybeans with sulfur, such as Gypsoil.

As the window for nutrient application closes for this year, talk to your Federated Agronomist to discuss the best options for your corn or soybean crops.